Tunable light sources have multiple and varied uses. Two particularly important applications for their use are chemical detection and optical communications applications.
The practical applications of chemical analysis now reach from the exotic environments of deep-sea exploration and outer space to the more mundane aspects of everyday life such as detecting emissions from a household gas furnace.
The Chemical and Biological Defense Information Analysis Center (CBIAC) has specifically identified forty-seven critical compounds and has begun the process of identifying various detection means, databases, and threshold limit values. The forty-seven compounds are grouped into eight categories: nerve agents, blood agents, toxins, blister agents, choking agents, incapacitating agents, riot control agents, and other. Of these, the first three are particularly important because of lethality at very low concentrations, and typically a variety of detection and discrimination means are required to cover all of the compounds.
Examples identified by CBIAC are shown below with threshold limit values (TLV). The required threshold values range over many orders of magnitude, but that the nerve agents, at the part per trillion (ppt) level, are by far the most stressing. It is estimated that approximately eighty percent of the compounds have TLVs greater than 1 part per billion (ppb).